AIRPLANE PERFORMANCES — HAMLIN AND SPENCELEY 435 



much in excess of 400 miles per hour are not obtainable. Curves for 

 both the propeller and turbojet are based upon maximum continuous 

 available thrust, which, unlike the ram-jet and rocket, are less than the 

 maximiun available as shown in figures 1, 2, and 3. Specific consump- 

 tion at maximum continuous thrust for the turbojet does not vary 

 significantly with air speed and improves appreciably at the higher 

 altitudes. 



Figure 5. — S. F. C. at maximum continuous thrust. 



In the case of the ram-jet, an entirely different variation is found. 

 Here, efficient operation is decidedly improved at extremely high 

 speeds, in the region of Mach Number =1.0, while at lower air speeds 

 the fuel consumption is prohibitively high, and, as seen from figures 1, 

 2, and 3, the maximum thrust available at low air speeds is exceedingly 

 small. Again, the ram-jet clearly belongs to the very high-speed 

 regime. 



As usual, the rocket is not influenced by speed or altitude, resulting 

 in a constant, but high, specific fuel consumption, since the oxygen to 

 support combustion must be included. 



